Antineoplastic polyalkoxyalkylsiloxanes and methods of use thereof

ABSTRACT

Polyaminofunctional alkoxy polysiloxanes which exhibit antineoplastic activity are disclosed. Pharmaceutical compositions including an effective amount of a polyaminofunctional alkoxy polysiloxane and/or a pharmaceutically acceptable salt thereof are also disclosed. The application also describes methods of suppressing the growth of neoplastic cells and treating neoplastic conditions.

BACKGROUND

In theory, drugs for the treatment of cancer and tumors should have thecapability to accomplish several key goals. First, the drug generallyshould be able to reach the area of the body where the disease/tumorresides (e.g., brain, lung, breast). The drug should preferably be ableto “target” diseased cells (i.e., differentiate between normal cells anddiseased cells). The drug should also generally be able to be totransverse various cellular membranes and/or to be “uptaken” by thediseased cell in order to interact with the constituents of that cell.The drug should preferably be able to “recognize” a critical diseaserelated entity (DNA/RNA/Protein) and be capable of binding to it in somefashion (i.e. anti-sense, nucleotide base π-stacking intercalation,triplex formation). Finally, the drug should terminate the diseaseentity's ability to function (grow) either by inhibition or destruction.The majority of cancer drugs currently in use fail, to a significantdegree, with respect to one or more of the attributes listed above. Inaddition, most cancer drugs currently in use are effective only againstvery specific types of cancer (i.e. “taxol” for ovarian cancer;“cis-platin” against lung, testicular, and neck tumors) and thus havelimited applicability. A single drug which has applicability against awide variety of cancerous cell lines would be a significant addition tothe current arsenal of chemotherapeutic drugs.

Through the use of mutant cell lines which did not require polyamines aswell and specific enzyme inhibitors, the metabolic cycle for polyamineshas been studied. This has led to several important findings; 1)polyamine levels are much higher in rapidly growing cells than innormally growing cells; 2) polyamines are required for cell growth(i.e., when cells are starved of polyamines, growth stops, but growthresumes to normal when exogenous polyamines are added to the cellculture media); 3) when needed, cells can uptake exogenous polyamines tosustain growth; 4) structural analogues of the natural polyamines canalso be taken up by cells from the exogenous media to approximately thesame degree as the natural polyamines but the structural analogues arenot metabolized within the cell; and 5) when polyamine levels become toohigh in the cell, polyamines are disposed of either by metabolicbreakdown of the polyamines or excretion from the cell.

It has been suggested by several researchers that the polyaminemetabolic system might be utilized in conjunction with chemotherapeuticprotocols. Probably the most intriguing aspect of this suggestion as itrelates to drug design is evidenced by recently reported research whichdemonstrated that: 1) many diseased cells, particularly cancer cells,have higher intracellular concentrations of the natural polyamines thando normal cells; 2) cells which have higher intracellular concentrationsof the natural polyamines take up polyamines in the exogenous media to amuch higher degree; and 3) some structural analogues of naturalpolyamines are taken up by cells from the exogenous media toapproximately the same degree as the natural polyamines but thestructural analogues are not metabolized within the cell. Taking thesefactors into consideration suggests that polyamines could represent amotif which might be utilized to simultaneously provide a cellularuptake vehicle as well as a cancer cell targeting capability.

SUMMARY

Aminofunctional alkoxy polysiloxane compounds and salts thereof, whichexhibit antineoplastic activity, are described herein. Theaminofunctional alkoxy polysiloxanes typically includes apoly((polyaminofunctional alkoxy) alkylsiloxane), such as apoly((diaminofunctional alkoxy) alkylsiloxane) compound. Theaminofunctional alkoxy polysiloxane can be a linear and/or cyclicpolysiloxane. The aminofunctional alkoxy group(s) in thepolyalkoxyalkylsiloxane can include primary, secondary and/or tertiaryamino functional groups. Particularly suitable examples of the presentaminofunctional alkoxy polysiloxane compounds includepolyalkoxyalkylsiloxanes containing one or more 1,3-diaminofunctionalalkoxy groups and/or 1,2-diaminofunctional alkoxy groups.

The present application also provides compositions which include apolyaminofunctional alkoxy polysiloxane compound and/or a salt thereof.Typically, the compositions include a pharmaceutically acceptablecarrier and the polyaminofunctional alkoxy polysiloxane compound and/ora pharmaceutically acceptable salt thereof.

Methods of suppressing the growth of neoplastic cells and treatingneoplastic conditions are also described herein. The method ofsuppressing the growth of neoplastic cells includes contacting theneoplastic cells with an effective amount of a polyaminofunctionalalkoxy polysiloxane compound and/or a salt thereof. As used herein,suppression of growth includes conditions where contacting neoplasticcells with a polyaminofunctional alkoxy polysiloxane results in slowergrowth of the cells, slower proliferation of the cells and/or more rapiddeath than normal of the cells. Examples of neoplastic cells whosegrowth can be suppressed by the present polyaminofunctional alkoxypolysiloxane compounds (and/or corresponding salt(s)) include neoplasticforms of lung, breast and central nervous system cells.

Pharmaceutical compositions including an effective amount of apolyaminofunctional alkoxy polysiloxane compound and/or apharmaceutically acceptable salt thereof can be used to treat neoplasms.Conditions associated with neoplastic forms of lung, breast and centralnervous system cells are examples of conditions which may be treatedusing the present compositions. Patient treatment using the presentmethod involves administering therapeutic amounts of the pharmaceuticalcomposition. As used herein, the terms “treat” and “therapy” and thelike refer to alleviation of clinical symptoms, slowing of theprogression, prophylaxis, attenuation or cure of existing disease. Inaddition, the terms “treat” and “therapy” can refer to preventing therecurrence and/or metathesis of neoplastic growth(s). It is desirable toadminister the composition in an amount which is effective to suppressthe growth of neoplasm cells and, more preferably, to cause neoplasticgrowths to shrink. As known to those of skill in the art, depending onthe particular type of neoplastic condition, the mode of administrationof the pharmaceutical composition may vary. In some instances, thecomposition may injected directly into a tumor while in others, it maybe more advantageous to administer the composition intravenously ororally.

DETAILED DESCRIPTION

The present invention relates to compositions that include anaminofunctional alkoxy polysiloxane compound and/or a salt thereof. Inmany instances, the compositions include a poly((aminofunctional alkoxy)alkylsiloxane) compound and/or a pharmaceutically acceptable saltthereof, together with a pharmaceutically acceptable carrier. Theaminofunctional alkoxy polysiloxane compound typically includes apolyaminofunctional alkoxy polysiloxane compound, such as apoly((diaminofunctional alkoxy) alkylsiloxane) compound.

As used herein, the terms “polyaminofunctional alkoxy polysiloxanecompound” and “polyaminofunctional alkoxy polysiloxane” are usedinterchangeably to refer to an alkoxy polysiloxane compound whichincludes one or more polyaminofunctional alkoxy groups. For the purposesof this application, the term polyaminofunctional alkoxy group refers togroups which include two or more amino groups and encompasses groupsresulting from the removal of a hydroxyl hydrogen atom from a polyaminofunctional alkanol (e.g., —O—CH₂CH₂NH—CH₂CH₂CH₂NH₂), a polyaminofunctional cycloalkanol, and/or a polyamino functionalhydroxy-substituted aryl compounds (e.g., —O—C₆H₄—CH₂CH₂NHCH₂CH₂NH₂). Asemployed herein, the term “aryl” refers to both hydrocarbon andheteroatom-containing aromatic groups. For example, thepolyaminofunctional alkoxy group may be an aminofunctional pyridyloxygroup (i.e., a group resulting from the removal of the hydroxyl hydrogenatom from an aminofunctional hydroxypyridine).

Amino groups are organic functional groups which contain a basicnitrogen atom. Examples of amino groups include aliphatic amino groups,such as mono-, di- and trialkylamino groups; cycloaliphatic aminogroups, such a piperidinyl and piperazinyl groups; aromatic amino groups(i.e, where the basic nitrogen atom is part of an aromatic ring), suchas pyridyl groups, pyrimidyl groups and pyrazinyl groups; andaminosubstituted aromatic groups (i.e., where the basic nitrogen atom isdirectly bonded to an aromatic group), such as aminophenyl groups (e.g.,—NH—C₆H₄ and —C₆H₄—NR₂).

As employed herein, the term “alkoxy group” encompasses functionalgroups which include an alkyl-OH, cycloalkyl-OH or aryl-OH functionalgroup whether or not the overall group includes an amino functionalgroup, i.e., an aminofunctional alkoxy groups constitute one type ofalkoxy group but not all alkoxy groups include a basic nitrogen atom.

As illustrated in formula (I) below, the siloxane subunits may not allcontain a polyaminofunctional alkoxy group. Typically, at least amajority and, in many instances, all of the siloxane subunits of thepolymer include a polyaminofunctional alkoxy group. Polysiloxanes wherenot all of the siloxane subunits of the polymer (with the exception ofthe terminal subunits) include the same group are referred to herein as“polysiloxane copolymers.” As used herein, such “copolymers” can havetwo or more different siloxane subunits. Polysiloxane copolymers can beformed by reacting a mixture of two alcohols, e.g., a mixture of2-aminoethanol and ethanol, with a polyalkylhydrosiloxane. Generally,the different siloxane subunits are randomly distributed in apolysiloxane copolymer (a “random copolymer”). However, by usingappropriate synthetic methods known to those of skill in the art,polysiloxane copolymers in which the different siloxane subunits arepresent in “blocks” of two or more identical adjacent subunits can alsobe produced (“block copolymers”). The present polysiloxane copolymerstypically have a ratio of siloxane subunits containing apolyaminofunctional alkoxy group to subunits which do not include apolyaminofunctional alkoxy group of at least about 1:4.

As used herein, the terms “diaminofunctional alkoxy polysiloxanecompound” and “diaminofunctional alkoxy polysiloxane” are usedinterchangeably to refer to an alkoxy polysiloxane which includes one ormore diaminofunctional alkoxy groups. A diaminofunctional alkoxy groupis a polyaminofunctional alkoxy group which includes two organicfunctional groups each having a basic nitrogen atom.

The present polyaminofunctional alkoxy polysiloxane compound may includelinear and/or cyclic aminofunctional alkoxy polysiloxane(s). The averagenumber of alkoxyalkylsiloxane subunits in the polyaminofunctional alkoxypolysiloxane compound can vary. For example, linear forms of the alkoxypolysiloxane compound may include from 2 to about 2,000 siloxanesubunits. Linear forms with no more than about 500 subunits and, moredesirably, 2 to about 100 subunits are quite suitable for use asantineoplastic agents. Cyclic forms of the alkoxy polysiloxane compoundtypically include from 3 to about 12 siloxane subunits and cyclic formswith 3 to 6 units are quite suitable.

Examples of suitable linear polyaminofunctional alkoxy polysiloxaneswhich can have antineoplastic properties include compounds having theformula I:

wherein n is an integer from 2 to 1,000 and m is an integer from 0 to1,000;

-   -   R¹, R¹ and R³ are independently C₁-C₁₀ alkyl, cyclopentyl,        cyclohexyl, benzyl, toluyl, xylyl or phenyl;    -   R⁴ is C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl,        xylyl or phenyl;    -   R⁵ is a polyaminofunctional alkoxy group;    -   R¹⁴ is hydrogen, C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl,        toluyl, xylyl or phenyl; and    -   R¹⁵ is C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl,        xylyl, phenyl, an alkoxy group, or an aminofunctional alkoxy        group. Typically, the ratio n/m is at least about 0.25, i.e., at        least about 20% of the siloxane subunits include a        polyaminofunctional alkoxy group. More commonly, a substantial        amount of the siloxane subunits include a polyaminofunctional        alkoxy group, e.g., at least about 50% of the subunits include        this type of functional group (i.e., the ratio n/m is at least        about 1.0). It is often desirable to select aminofunctional        polysiloxanes where R¹⁴ is not hydrogen, e.g., where all of the        non-alkoxy substituents on the silicon atoms of the polymer are        alkyl, cycloalkyl, benzyl and/or phenyl groups.

Commonly, R¹, R² and R³ are independently C₁-C₆ alkyl. Linearpoly((diaminofunctional alkoxy) alkylsiloxane) compounds in which R¹,R², R³ and R⁴ are methyl groups are quite suitable for use as neoplasticagents.

Examples of suitable cyclic polyaminofunctional alkoxy polysiloxaneswhich can have antineoplastic properties include compounds having theformula II:

wherein q is an integer from 1 to 12; z is an integer from 0 to 11; andq+z=an integer from 3 to 12;

-   -   R⁴ is C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl,        xylyl or phenyl;    -   R⁵ is a polyaminofunctional alkoxy group;    -   R¹⁴ is hydrogen, C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl,        toluyl, xylyl or phenyl; and    -   R¹⁵ is C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl,        xylyl, phenyl, an alkoxy group, or an aminofunctional alkoxy        group. Cyclic polysiloxanes in which q/z is at least 1.0 and,        more desirably, at least 2.0 are quite suitable for use as        neoplastic agents. It is often desirable to select cyclic        aminofunctional polysiloxanes where R¹⁴ is not hydrogen, e.g.,        where all of the non-alkoxy substituents on the silicon atoms of        the polysiloxane are alkyl, cycloalkyl, benzyl and/or phenyl        groups.

The present polyaminofunctional alkoxy polysiloxanes desirably include a1,3-diaminofunctional alkoxy group and/or a 1,2-diaminofunctional alkoxygroup. Suitable examples of such diaminofunctional alkoxy groups include1,3-diaminofunctional alkoxy groups having the formula (III):

wherein R⁶, R⁷, R⁸ and R⁹ are independently hydrogen or C₁-C₆ alkyl, orR⁶ and R⁷ form a C₃-C₈ cyclic group or R⁸ and R⁹ form a C₃-C₈ cyclicgroup. Specific examples of such 1,3-diaminofunctional alkoxy groupsinclude

Other examples of suitable polyaminofunctional alkoxy polysiloxanesinclude a 1,3- and/or 1,2-diaminofunctional alkoxy group having theformula IV:—O—CH₂CH₂NR¹⁰(CH₂)_(q)NR¹¹R¹³  (IV)where q is 2 or 3; and R¹⁰, R¹¹ and R¹² are independently hydrogen orC₁-C₆ alkyl, or R¹¹ and R¹² form a C₃-C₈ cyclic group. Specific examplesof such diaminofunctional alkoxy groups include

-   -   —O—CH₂CH₂NHCH₂CH₂NMe₂, —O—CH₂CH₂NHCH₂CH₂CH₂NMe₂,    -   —O—CH₂CH₂NMeCH₂CH₂NMe₂, —O—CH₂CH₂NMeCH₂CH₂CH₂NMe₂,    -   —O—CH₂CH₂NHCH₂CH₂NH₂, and —O—CH₂CH₂NHCH₂CH₂CH₂NH₂.

The present compositions are useful as antineoplastic agents and areparticularly effective at inhibiting the growth and/or killingneoplastic cells and for treating neoplastic pathologies. Thepolyaminofunctional alkoxy polysiloxanes can be used in pharmaceuticalcompositions for treatment of neoplastic pathologies. It is anticipatedthat the pharmaceutical compositions of the present invention can beused to treat a variety of neoplastic conditions. In particular, thepresent compositions are useful for treatment of conditions associatedwith neoplastic forms of lung, breast and central nervous system cells.

Polyaminofunctional alkoxy polysiloxanes can be prepared by reacting thecorresponding linear polyhydrosiloxane and/or cyclic polyhydrosiloxanewith an aminoalcohol. As used herein, the term “aminoalcohol” includesamino functional hydroxy substituted alkyl, cycloalkyl, aralkyl and arylcompounds. The reaction of the polyhydrosiloxane and the aminoalcohol istypically carried out in the presence of a dehydrogenative couplingcatalyst, such as those catalysts known to be useful for thedehydrogenative coupling of silanes. Suitable dehydrogenative couplingcatalysts include catalysts which have been employed in metal catalyzeddehydrogenative coupling of silanes and alcohols, such as thoseincluding Pd, Cu, Mn, Ni, Rh and/or Ru species. Other suitabledehydrogenative coupling catalysts may include Pt, Zn, Ir, Cr, and/or Tispecies. The dehydrogenative coupling catalysts may be a mixed metalcatalyst that includes more than one metal species. Specific examples ofsuitable catalysts for the dehydrogenative coupling of silanes andalcohols include the catalysts shown in Table 1 below.

TABLE 1 10% Pd/C H₃SiMn(CO)₅ Cu(O) metal Mn₂(Co)₁₀ CuCl/LiO(t-C₄H₉) Pd/CCuClCN/LiO(t-C₄H₉) PdCl₂[P(C₆H₅)₃]₃ CuO(t-C₄H₉)/(C₄H₉)₄NCl Raney NiRuCl₂[P(C₆H₅)₃]₃ tris(dibenzylideneacetone)dipalladium(0)-chloroform

Particularly suitable catalysts include rhodium catalysts and, moredesirably, catalysts which include rhodium(I) species, such asphosphine-containing rhodium(I) catalysts. Suitable examples ofphosphine-containing rhodium(I) catalysts include tris-phosphinorhodium(I) salts, such as RhCl(P(C₆H₅)₃)₃ (known as “Wilkinson'scatalyst”), RhCl(P(CH₂CH₂(CF₂)_(n=6-8)CF₃)₃)₃ and RhCl(P(C₆H₁₁)₃)₃.Examples of additional suitable rhodium catalysts include the compoundsshown in Table 2.

TABLE 2 (η⁶-C₆H₆B(C₆H₆)₃)Rh(cod) Rh(CO)₂(acac) ((C₈H₁₄)₂RhCl)₂Rh(cod)B(C₆H₅)₄ ((RhCl(CH₂═CH₂)₂)₂) Rh(C₈H₁₂)₂BF₄/P(C₆H₅)₃ (RhCl₂(CO)₂)₂Rh₂Co₂(CO)₁₂ 5% Rh/C Rh₄(CO)₁₂ Co₂Rh₂(CO)₁₂ Rh₄(CO)₁₂/NEt₃ Co₃Rh(CO)₁₂Rh/C Rh/Al₂O₂

The dehydrogenative coupling reaction between thepoly(alkylhydrosiloxane) and the aminoalcohol is commonly carried outunder relatively anhydrous, deoxygenated conditions. This may beconveniently achieved by degassing the reaction mixture and carrying thereaction out under an inert gas atmosphere (e.g., under a dry nitrogenor argon atmosphere). The reaction is typically conducted at atemperature of about 60-100° C. over a period of about 1-48 hours. Thereaction mixture may initially become yellow in color and emit gas(presumably H₂), and may later become red/orange as the gas emissionsubsides. Spectroscopic methods, such as NMR and/or IR analysis of thereaction mixture, may be utilized to establish the point at whichrelatively complete reaction of the Si—H functionalities has beenachieved. For example, the reaction progress can be monitored by theresidual Si—H and O—H stretches that fall in a convenient window of theIR spectrum. The amount of incorporation of the alcohol into the desiredproduct can also be determined by monitoring NMR signals assigned tospecific components.

Examples of reactions which can be used to produce linearpoly((aminofunctional-alkoxy)-alkylsiloxane) compounds from varyingaminoalcohols (“ROH”) and the corresponding linearpoly(allylhydrosiloxane) are shown in the following scheme:

Similar reactions can be used to produce cyclic poly((aminofunctionalalkoxy)-alkylsiloxane) compounds from an aminoalcohol and thecorresponding cyclic poly(alkylhydrosiloxane).

The pharmaceutical compositions of the present invention include apolyaminofunctional alkoxy polysiloxanes in effective unit dosage formand a pharmaceutically acceptable carrier. The specification for thedosage unit forms of the polyaminofunctional alkoxy polysiloxanes aredictated by and directly depend on among other factors (a) the uniquecharacteristics of the active material and the particular therapeuticeffect to be achieved; (b) the limitations inherent in the art ofcompounding such active material for the treatment of disease; and (c)the manner of intended administration of the dosage unit form. Theprincipal active ingredient is typically compounded for convenient andeffective administration in effective amounts with a suitablepharmaceutically acceptable carrier in dosage unit form as disclosedherein. As used herein, the term “effective unit dosage” or “effectiveunit dose” is denoted to mean a predetermined amount sufficient to beeffective against the neoplastic cells in vivo. Pharmaceuticallyacceptable carriers are materials useful for the purpose ofadministering the medicament, which are preferably non-toxic, and can besolid, liquid, or gaseous materials, which are otherwise inert andmedically acceptable and are compatible with the active ingredients. Thepharmaceutical compositions can contain other active ingredients such asantimicrobial agents, antiviral agents, and other agents such aspreservatives.

Water, saline, aqueous dextrose, and glycols are suitable liquidcarriers, particularly (when isotonic) for injectable solutions. Thecarrier can also include various oils, such as those of petroleum,animal, vegetable or synthetic origin, for example, peanut oil, soybeanoil, mineral oil, sesame oil, and the like. Suitable pharmaceuticalexcipients include starch, cellulose, talc, glucose, lactose, sucrose,gelatin, malt, rice, flour, chalk, silica gel, magnesium stearate,sodium stearate, glycerol monostearate, sodium chloride, dried skimmilk, glycerol, propylene glycol, water, ethanol, and the like. Thecompositions can be subjected to conventional pharmaceutical expedients,such as sterilization, and can contain conventional pharmaceuticaladditives, such as preservatives, stabilizing agents, wetting, oremulsifying agents, salts for adjusting osmotic pressure, buffers, andthe like. Suitable pharmaceutical carriers and their formulations aredescribed in Martin, “Remington's Pharmaceutical Sciences,” 15th Ed.;Mack Publishing Co., Easton (1975); see, e.g., pp. 1405-1412 and pp.1461-1487. Such compositions will, in general, contain an effectiveamount of the active compound together with a suitable amount of carrierso as to prepare the proper dosage form for proper administration to thehost.

These pharmaceutical compositions can be administered parenterally,including by injection; orally; used as a suppository or pessary;applied topically as an ointment, cream, aerosol, powder; or given aseye or nose drops, etc., depending on whether the preparation is used totreat internal or external viral infections. The compositions cancontain 0.1%-99% of the active material. For topical administration, forexample, the composition will generally contain from 0.01% to 20%, andmore typically 0.5% to 5% of the active material.

The present invention is also drawn to methods of treating neoplasticconditions using the present pharmaceutical compositions. Typically, thecompositions will be administered to a patient (human or other animal,including mammals such as, but not limited to, cats, horses and cattleand avian species) in need thereof, in an effective amount to amelioratethe symptoms of the neoplastic condition. It is desirable to administerthe composition in an amount which is effective to suppress the growthof the neoplasm and, more preferably, to cause the neoplasm to shrink.The present compositions can be administered by a variety of methods,e.g., orally, intravenously, intramuscularly or topically.

For oral administration, fine powders or granules can contain diluting,dispersing and/or surface active agents, and can be presented in adraught, in water or in a syrup; in capsules or sachets in the dry stateor in a non-aqueous solution or suspension, wherein suspending agentscan be included; in tablets or enteric coated pills, wherein binders andlubricants can be included; or in a suspension in water or a syrup.Where desirable or necessary, flavoring, preserving, suspending,thickening, or emulsifing agents can be included. Tablets and granulesare preferred, and these can be coated. For buccal administration, thecompositions can take the form of tablets or lozenges formulated in aconventional manner. For parenteral administration or for administrationas drops, as for conditions of the eye, the compounds can be presentedin aqueous solution, e.g., in a concentration of from about 0.1 to 10%,more preferably 0.5 to 2.0%, most preferably 1.2% w/v. The solution cancontain antioxidants, buffers, and the like.

The compositions according to the invention can also be formulated forinjection and can be presented in unit dose form in ampoules or inmulti-dose containers with an added preservative. The compositions cantake such forms as suspensions, solutions, or emulsions in oily oraqueous vehicles, and can contain formulatory agents such as suspending,stabilizing, and/or dispersing agents. Alternatively, the activeingredient can be in powder form for constitution with a suitablevehicle, e.g., sterile, pyrogen-free buffer saline, before use. Thepresent compositions can also be in the form of encapsulated liposomes.

Alternatively, for infections of the eye or other external tissues,e.g., mouth and skin, the compositions are preferably applied to theinfected part of the body of the patient as a topical ointment or cream.The compounds can be presented in an ointment, for instance with awater-soluble ointment base, or in a cream, for instance with an oil inwater cream base, in a concentration of from about 0.1 to 1% (w/v), moredesirably 0.5 to 2.0% (w/v). For topical administration, the dailydosage as employed for adult human treatment will range from 0.1 mg to1000 mg. However, it will be appreciated that extensive skin conditionsmay require the use of higher doses.

The present invention may be better understood with reference to thefollowing examples. These examples are intended to be representative ofspecific embodiments of the invention, and are not intended as limitingthe scope of the invention.

EXAMPLES

All reactions were carried out under an atmosphere of argon. Airsensitive products and reagents were handled by standard Schlenktechniques. All solvents were dried and distilled from purple solutionsof sodium/benzophenone or P₂O₅, and glassware was dried in an oven at110-120° C. prior to use. Poly(methylhydro)siloxaneMe₃Si—(O—SiMeH—)_(n)-O—SiMe₃ (M_(w) ^(˜)2000; n=33-35) and RhCl(PPh₃)₃(99.99%) were obtained from Aldrich and used as received. Commerciallyavailable alcohols were generally used as such without any furtherpurification.

²⁹Si, ¹³C, ¹H NMR spectra were recorded on JEOL GSX270 and GSX400spectrometers. ¹H and ¹³C chemical shifts were measured against Me₄Siusing solvent resonances as standard locks. ²⁹Si chemical shifts werereferenced to external Me₄Si in the same solvent. Molecular weight ofthe polymers was determined by Waters GPC with polystyrene as standardand THF as solvent. IR spectra were recorded on a Matheson Instruments2020 Galaxy Series spectrometer as KBr pellets or solutions in CaF₂cells.

Example 1

Deuterobenzene (1 ml), amino alcohol (0.02 mol), and [(C₆H₅)₃P]₃RhCl(0.162 g, 0.0002 mol) were introduced to a 25 ml Schlenk tube containinga magnetic stirring bar and sealed with a rubber septum. Thesecomponents were degassed via 5 freeze/pump/thaw cycles and infused withargon. Linear or cyclic poly(alkylhydrosiloxane) (0.02 mol) was injectedinto a reaction tube via a syringe while the other reactants were stillfrozen (to minimize autocatalization by amine moieties) and 5 additionalfreeze/pump/thaw cycles were performed to further degas the reactionmixture.

At this time, the reaction tube was submerged in a silicon oil bathpreheated to 80° C. As all of the reactants became homogenous, thereaction mixture generally turned bright yellow in color and vigorousgas evolution (presumably H₂) was observed immediately. The reactiontube was kept under positive argon pressure during the entire course ofthe reaction in order to flush the H₂ gas from the reaction mixture.After approximately one hour, the reaction mixture became red/orange andthe gas evolution subsided, the solution was stirred at 80° C. for anadditional hour to ensure complete conversion. NMR and IR samples wereextracted via a syringe and used to confirm complete conversion.

One of two methods were used to remove the spent catalyst:

Method A:

The reaction mixture was flushed through a 5 ml syringe that contained aKimwipe plug at the bottom, followed by a 3 ml silica gel plug (neutral,dried under vacuum, and subsequently saturated with either benzene ortoluene). On the occasions that excess aminoalcohol was present in theproduct mixture, it was removed by flushing the product mixture througha silica-gel plug (1 inch×1 cm diameter) with toluene where theaminoalcohol was isolated as a secondary eluant.

Method B:

The reaction mixture was allowed to sit for two days at ambienttemperature, after which the catalysts had precipitated out of solutionas a red solid. The supernatant was removed from the solid with asyringe.

After using Method A or Method B the catalyst could generally not bedetected by NMR in the product solution (catalyst arene substituent ¹Hδ=7.17 m, 7.65 m; ¹³C δ=128.92, 129.08, 132.14, 132.60, 132.723). Thesolvent was then typically removed under reduced pressure.

Example 2 Synthesis of bis-(trimethylsiloxy)-1,3-dimethyl,1,3-(1,3-(N,N-dimethylamino)-2-propoxy)siloxane, 5

The synthesis was carried out using the general procedure describedabove in Example 1 with the linear poly(alkylhydrosiloxane),1,3-bis(trimethylsiloxy)-1,3-dimethylhydrosiloxane 1 (n=2), where1,3-(N,N-dimethylamino)-2-propanol (3.26 ml, 0.02 mol) was used as theamino alcohol. Method B was used to isolate the desired product 5 (n=2)in 97% yield.

¹H▭=0.22 (s, 24H, —OSi(CH₃)₃), 0.26 (s, 6H, —OSi(CH₃)[(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 2.22 (s, 12H, (CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 2.44 (dm,4H, (CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 4.15 (p, 1H,(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂).

¹³C▭=−2.53 (—OSi(CH₃)[CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 1.87 (—OSi(CH₃)₃),46.55 ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 64.32 ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂),69.99 ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂). ²⁹Si▭=−59.34 & −58.40 (rac & mesodiads, —OSi(CH₃)[(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 7.99 & 7.74 (rac & mesodiads, —OSi(CH₃)₃).

Example 3 Synthesis ofpoly(1,3-N,N-dimethylamino-2-propoxy)methylsiloxane, 6

The synthesis was carried out using the general procedure describedabove in Example 1 with linear poly(alkylhydrosiloxane) 2 (n=32-35)where 1,3-(N,N-dimethylamino)-2-propanol (3.26 ml, 0.02 mol) was used asthe amino alcohol. Method B was used to isolate the desired product 6(n=32-35) in 97% yield.

¹H▭=0.25 (s, 24H, —OSi(CH₃)₃), 0.38 (s, 6H, —OSi(CH₃)[(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 2.22 (s, 12H, (CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 2.44 (dm,4H, (CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 4.42 (p, 1H,(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂).

¹³C▭=−2.72 (—OSi(CH₃)[CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 1.87(—OSi(CH₃)_(3),) 46.73 ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 64.59 ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 70.02 ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂).²⁹Si▭=−58.0 to −61.0 (multiple peaks,—OSi(CH₃)[(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 9.21 to 8.92 (multiple peaks,—OSi(CH₃)₃).

The antineoplastic activity ofpoly(1,3-N,N-dimethylamino-2-propoxy)methylsiloxane, 6, against severalcancer cell lines was examined using the protocol described in Example7. Aminofunctional alkoxy polysiloxane 6 exhibited antineoplasticactivity against the three cancer cells lines tested, Hs578T breastcancer cells, MCF-7 breast cancer cells, and NCI-H460 lung cancer cells.The concentration of polysiloxane 6 required to kill 100% of the cellswas 4-32 fold lower for the two breast cancer cell lines than for anormal breast cell line (MCF-12A normal breast cell line).

Example 4 Synthesis ofcyclotetra(1,3-N,N-dimethylanzino-2-propoxy)methylsiloxane, 8

The synthesis was the same as the procedure described above in Example 1except that cyclotetra(methylhydro)siloxane (7) (1.21 ml, 0.02 mol) wasas the cyclic poly(alkylhydrosiloxane) and1,3-(N,N-dimethylamino)-2-propanol (3.26 ml, 0.02 mol) was used as theamino alcohol. Method B was used to isolate the desired product 8 in 98%yield.

¹H▭=0.42 (s, 6H, —OSi(CH₃)[(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 2.22 (s, 12H,(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 2.47 (dm, 4H, (CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂),4.22 (p, 1H, ((CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂).

¹³C▭=−2.37 (—OSi(CH₃)[CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—), 46.98(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 64.92 (CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂), 70.65(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂). ²⁹Si▭=−58.0 to −60.60 (multiple peaks—OSi(CH₃)[(CH₃)₂NCH₂CH(—O)CH₂N(CH₃)₂]O—).

Example 5 Synthesis ofbis-(trimethylsiloxy)-1,3-dimethyl-1,3-(3-amino-1-propoxy)siloxane, 3

Deuterobenzene (1 ml), 3-amino-1-propanol (1.51 ml, 0.02 mol), and((C₆H₅)₃P)₃RhCl (0.162 g, 0.0002 mol) were introduced to a 25 ml Schienktube containing a magnetic stirring bar and sealed with a rubber septum.These components were degassed via 5 freeze/pump/thaw cycles and infusedwith argon. 1,3-Bis(trimethylsiloxy)-1,3-dimethylhydrosiloxane 1 (3.30ml, 0.02 mol) was injected into the reaction tube via a syringe whilethe other reactants were still frozen (to minimize autocatalization bythe amine moieties) and 5 additional freeze/pump/thaw cycles wereperformed in order to further degas the reaction mixture.

At this time, the reaction tube was submerged in a silicon oil bathpreheated to 80° C. As all of the reactants became homogenous, thereaction mixture became bright yellow in color and vigorous gasevolution (presumably H₂) was observed immediately. The reaction tubewas kept under positive argon pressure during the entire course of thereaction in order to flush the H₂ gas from the reaction mixture. Afterapproximately one hour, the reaction mixture became red/orange and thegas evolution subsided. The solution was stirred at 80° C. for anadditional hour to ensure complete conversion. NMR and IR samples wereextracted via a syringe and indicated complete conversion.

The reaction mixture was allowed to sit for two days at ambienttemperature, after which the catalysts had precipitated out of solutionas a red solid. The supernatant was removed from the solid with asyringe. Catalyst could not be detected by NMR in the product solution(catalyst arene substituent ¹H δ=7.17 m, 7.65 m; ¹³C δ=128.92, 129.08,132.14, 132.60, 132.723). The solvent was removed via reduced pressureto produce the desired product 3 (n=2) in an isolated yield of 95%.

¹H▭=0.104 (s, 1H, —OSi(CH₃)₃), 0.08 (s, 3H, —OSi(CH₃)(OCH₂CH₂CH₂NH₂)O—),0.78 (bs, 2H, —OCH₂CH₂CH₂NH₂), 1.52 (p, 2H, —OCH₂CH₂CH₂NH₂, J₂₋₁=6.35Hz, J₂₋₃=6.61 Hz), 2.63 (t, 2H, —OCH₂CH₂CH₂NH₂, J₂₋₃=6.61 Hz), 3.74 (t,2H, —OCH₂CH₂CH₂NH₂, J₁₋₂=6.35 Hz). ¹³C▭=−4.14(—OSi(CH₃)(OCH₂CH₂CH₂NH₂)O—), 1.43 (—OSi(CH₃)₃), 36.31 (—OCH₂CH₂CH₂NH₂),38.85 (—OCH₂CH₂CH₂NH₂), 59.88 (—OCH₂CH₂CH₂NH₂). ²⁹Si▭=−57.74 & −57.77(rac & meso diads —OSi(CH₃)(OCH₂CH₂CH₂NH₂)O—), 8.65 & 8.62 (rac & mesodiads, —OSi(CH₃)₃). IR in C₆D₆: —NH₂ absorbances at 3391 cm⁻¹ and 3310cm⁻¹.

Example 6

For the past 10 years, the Developmental Therapeutics Program (DTP) ofthe National Cancer Institute (NCI) has used an in vitro modelconsisting of 60 human tumor cell lines as the primary anticancer screen(see, J. Natl. Cancer Inst., 83:757-766, (1991)). An analysis of thedata from this screening program has indicated that approximately 95% ofthe antineoplastic activities from the 60 cell line screen can beidentified using only three cell lines. In view of this, the DTP nowuses a 3-cell line panel consisting of the MCF7(breast carcinoma) cellline, the NCI-H460 (lung carcinoma) cell line, and the SF-268 (CNSglioma) cell line as its primary anticancer (antineoplastic) assay. This3-cell line, single-dose assay has been in use by DTP for several yearsfor the evaluation of combinatorial libraries and has proven to be aneffective pre-screen for compounds with antineoplastic activity.

In the DTP protocol, each cell line is inoculated and preincubated on amicrotiter plate. Test agents are then added at a single concentrationand the culture incubated for 48 hours. End-point determination are madewith sulforhodamine B, a protein-binding dye. Results for each testagent are reported as the percent of growth of the treated cellsnormalized against the growth of the corresponding untreated controlcells, i.e., a reported value of +100% refers to cell growth equivalentto that of the corresponding untreated control cells. Negativepercentage refer to treatments which resulted in a smaller number ofcells at the end of the test versus the beginning, i.e., a portion ofthe cells had been killed by the treatment. Compounds which reduce thegrowth of any one of the cell lines to a value of +32% or less (negativenumbers indicate cell kill) are generally considered to be sufficiently“active” to be selected for further evaluation by NCI in a full panel of60 tumor cell lines over a 5-log dose range.

Two poly((aminofunctional alkoxy)-alkylsiloxane) compounds were testedfor antineoplastic activity in the DTP screen. The two compounds (linearpoly((aminofunctional alkoxy)-alkylsiloxanes) 5 and 3) were preparedaccording to the procedures described in Examples 2 and 5 above,respectively. The results of the DTP screen are shown in Table 3 below.The poly((diaminofunctional alkoxy) alkylsiloxane) compound preparedaccording to the procedure of Example 2 (Compound 5) showedantineoplastic activity against all three test cell lines in the DTPscreen. This compound includes 1,3-N,N-dimethylamino-2-propoxy groups.The corresponding analog with 3-amino-1-propoxy groups (Compound 3) wasinactive in this DTP screen.

TABLE 3 Growth Percentages Compound Sample (Lung) (Breast) (CNS) IDConcentration NCI-H460 MCF7 SF-268 Activity Compound 5 1.00 E-04 Molar−16 −5 −24 Active (Example 2) Compound 3 1.00 E-04 Molar Inactive(Example 5)

Example 7

An additional screening protocol can be used to examine the potentialantineoplastic activity of smaple compounds. The chemicals were testedusing a Neutral red assay to determine the viability of cells in theculture via a procedure based on that described in Babich et al.,Alternatives to Laboratory Animals 18:129-144 (1990) and Babich et al.,In Vitro Methods in Toxicology, Chapter 17, pp. 237-251, Watson RR (ed.)CRC Press, Boca Raton, Fla. (1992). Neutral red dye(3-amino-7-dimethyl-2-methylphenazine hydrochloride) is a water-soluble,weakly basic, spravital dye that accumulates in lysosomes of viablecells. Thus, the relative viability of a culture can be determined bycomparing the control cultures to the test cultures. The quantitation ofthe extracted dye spectrophotometrically has been correlated with thenumber of viable cells using direct cell counts and proteindeterminations (see, e.g., Borenfreund et al., Journal of Tissue CultureMethods 8:7-9 (1984); and Borenfreund et al., Toxicology Letters24:119-124 (1985)).

Cells to be tested were grown in 150 cm² flasks in the appropriatemedium at 37° C. until confluent. The cells were removed from the flaskusing trypsin, suspended in a single-cell suspension in appropriatemedium, and added to 96-well trays (3 96-well trays per 150 cm² flask).The cells were incubated at 37° C. for 24 hours, which resulted in aconfluent monlayer. Samples of chemicals to be tested were diluted inappropriate medium to 100 ug/ml followed by 10, 1:2 dilutions of eachtest sample. The medium on the 96-well trays was aspirated. For testsamples, 150 ul of each sample dilution were added to each of 8 wellsfollowed by 150 ul of culture medium. The trays were incubated at 37° C.

After 48 hours incubation, the medium was removed from all wells, thecells rinsed once with 200 ul of phosphate buffered saline (pH 7.2), 50ul of Neutral red stain (40 ug/ul) was added to every well, and thetrays incubated at 37° C. Following 3 hours incubation, the neutral redwas removed, wells were rinsed with 50 ul of formol/calcium (0.5%formaldehyde and 1.0% calcium), and 200 ul of acetic ethanol (1.0%acetic acid and 50% ethanol) were added. Following 30 minutes at roomtemperature and rapid agitation for a few seconds, the trays werescanned in a microplate reader (spectrophotometer) at a wavelength of540-nm.

Titers were determined as the dilution 100% end-point—or the reciprocalof the highest dilution where 100% of the cells were killed, relative tothe controls (no test sample).

The invention has been described with reference to various specific andpreferred embodiments and techniques. The invention is not to beconstrued, however, as being limited to the specific embodimentsdisclosed in the specification. It should be understood that manyvariations and modifications may be made while remaining within thespirit and scope of the invention.

Statement Regarding Federally Sponsored Research

The U.S. Government has a paid-up license in the present invention andthe right (in limited circumstances) to require the patent owner tolicense others on terms as provided for by the terms of Grant Nos.F49620-96-1-0360 and F49620-99-0283 awarded by the Air Force Office ofScientific Research and Grant No. 9874802 awarded by the NationalScience Foundation.

1. An aminofunctional alkoxy polysiloxane having the formula:

wherein n is an integer from 2 to 1,000; m is an integer from 0 to1,000; and at least about 20% of the siloxane subunits include apolyaminofunctional alkoxy group; R¹, R², and R³are independently C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl, xylyl or phenyl; R⁴is C₁- C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl, xylyl orphenyl; R¹⁴ is hydrogen, C1- C10 alkyl, cyclopentyl, cyclohexyl, benzyl,toluyl, xylyl or phenyl; R¹⁵ is C₁- C₁₀ alkyl, cyclopentyl, cyclohexyl,benzyl, toluyl, xylyl, phenyl, or an alkoxy group; and R⁵ is

wherein R⁶, R⁷, R⁸, and R⁹are independently hydrogen or C₁- C₆ alkyl, orR⁶and R⁷form a C₃- C₈ cyclic group or R⁸ and R⁹ form a C₃- C₈ cyclicgroup.
 2. The polysiloxane of claim 1, wherein m is
 0. 3. Thepolysiloxane of claim 1, wherein m is 0 and n is
 2. 4. The polysiloxaneof claim 1, wherein m + n is from 2 to about
 100. 5. The polysiloxane ofclaim 1, wherein R¹, R², R³, R⁴, R¹⁴ and R¹⁵ are C₁-C₆ alkyl.
 6. Thepolysiloxane of claim 1, wherein R¹, R², R³, R⁴, R¹⁴ and R¹⁵ are methyl.7. The polysiloxane of claim 1, wherein R⁵ is


8. The polysiloxane of claim 1, wherein m is 0; n is an integer from 2to 50; and R⁵ is


9. The polysiloxane of claim 1, wherein m is 0; R¹, R², R³, R⁴, R¹⁴ andR¹⁵ are methyl; and R⁵ is


10. The polysiloxane of claim 1, wherein R⁶, R⁷, R⁸, and R⁹ are C₁- C₆alkyl.
 11. The polysiloxane of claim 10, wherein R¹, R², R³, R⁴, R¹⁴ andR¹⁵ are methyl.
 12. An aminofunctional alkoxy polysiloxane having theformula:

wherein n is an integer from 2 to 1,000; m is an integer from 0 to1,000; and at least about 20% of the siloxane subunits include apolyaminofunctional alkoxy group; R¹, R² and R³ are independently C₁-C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl, xylyl or phenyl; R⁴is C₁- C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl, toluyl, xylyl orphenyl; R¹⁴ is hydrogen, C₁- C₁₀ alkyl, cyclopentyl, cyclohexyl, benzyl,toluyl, xylyl or phenyl; R¹⁵ is C₁- C₁₀ alkyl, cyclopentyl, cyclohexyl,benzyl, toluyl, xylyl, phenyl, or an alkoxy group; and R⁵ is-O-CH₂CH₂NR¹⁰(CH₂)_(q)NR¹¹R¹²; and q is 2 or 3; and R¹⁰ is hydrogen orC₁- C₆ alkyl; and R¹¹ and R¹² are independently C₁- C₆ alkyl, or R¹¹ andR¹² form a C₃- C₈ cyclic group.
 13. The polysiloxane of claim 12,wherein q is
 2. 14. The polysiloxane of claim 12, wherein q is
 3. 15.The polysiloxane of claim 12, wherein R¹⁰ is C₁-C₆ alkyl; and R¹¹ andR¹² are independently C₁- C₆ alkyl.
 16. The polysiloxane of claim 12,wherein R¹¹ and R¹² are methyl.
 17. The polysiloxane of claim 12,wherein R⁵ is —OCH₂CH₂NHCH₂CH₂NMe₂.
 18. The polysiloxane of claim 12,wherein R⁵ is —OCH₂CH₂NMeCH₂CH₂NMe₂.
 19. The polysiloxane of claim 12,wherein R¹⁰ is hydrogen.
 20. The polysiloxane of claim 12, wherein R¹⁰is methyl
 21. The polysiloxane of claim 12, wherein m is
 0. 22. Thepolysiloxane of claim 12, wherein m is 0 and n is
 2. 23. Thepolysiloxane of claim 12, wherein m + n is from 2 to about
 100. 24. Thepolysiloxane of claim 12, wherein the polysiloxane is a randomcopolymer.
 25. The polysiloxane of claim 12, wherein R⁵ is—OCH₂CH₂NMeCH₂CH₂CH₂NMe₂.